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Low temperature economizer

Improve the efficiency of recycling, reduce coal consumption;
Improve the efficiency of dust removal (installed before the dust collector);
Reduce the evaporation of desulfurization tower, saving water.
brief introduction:

Exhaust heat loss is the largest of the heat loss of the power plant boiler, usually 5% to 8%, accounting for 80% of the total heat loss of the boiler or higher. The main factors that affect the heat loss of the exhaust gas are the boiler exhaust temperature.

  • Product introduction
  • Performance advantage
  • technical parameter
  • cases

Product introduction

Exhaust heat loss is the largest of the heat loss of the power plant boiler, usually 5% to 8%, accounting for 80% of the total heat loss of the boiler or higher. The main factors that affect the heat loss of the exhaust gas are the boiler exhaust temperature. Under normal circumstances, the exhaust heat temperature increases by 10 ℃ and the exhaust heat loss increases by 0.6% ~ 1.0%. 1 China's current thermal power units in the boiler exhaust gas temperature is generally around 125 ~ 150 ℃, the actual smoke temperature is higher than the design value is ubiquitous phenomenon.

The company and Xi'an Jiaotong University and other well-known domestic research institutions, developed a highly efficient energy-saving low-temperature waste heat recovery system which is in leading position in the boiler tail flue heat recovery technology in the domestic market.

"Low temperature economizer", can greatly reduce the flue gas temperature, so that the flue gas temperature be reduced lower 40 ~ 50 ℃ or more. The energy absorbed by the "low temperature economizer" can be used to heat the condensate or to increase the temperature of the combustion air by heating the air through the heater. Power plant boiler using "low temperature economizer", can save 1 ~ 4g / kWh, unit efficiency increased by 0.2 to 1.2%. "Low temperature economizer" in the full recovery and utilization of exhaust heat at the same time, but also to achieve the best desulfurization efficiency of smoke temperature, greatly reducing the desulfurization tower to reduce the smoke and water spray cooling water consumption. Under normal circumstances, it takes 1 ~3 years for power plant 1 to recover the investment in "low temperature economizer" and its system equipment , that is to say, the economic benefits are enormous.

Performance advantage

Economic analysis

Flue gas waste heat recovery economy is a sensitive topic, how to obtain the greatest economic benefits and recover the investment in a shortest possible time? That's what the most users concerned. This issue needs to be based on the availability of flue gas temperature difference, the use of heat recovery Specific issues Specific analysis:

1. Application of flue gas waste heat recovery system for tail flue of power plant boiler

The thermal temperature is low, usually 100℃ or so with not good quality. This part of the recovery of heat is not equivalent to the method of calculation, but should be equivalent conversion method or heat balance calculation to determine the effective use of heat recovery value (thermodynamics second law).

工况

抽取凝结水温度℃

凝结水在烟气换热器出口温度℃

汽轮机热耗kj/kw.h

相对原工况差值kj/kw.h

发电煤耗差值g/kw.h

无烟气换热器(原工况)

——

——

8436.42

0

0

方案一

35.5

66.61

8398.17

38.25

1.31

方案二

35.5

85

8381.74

54.68

1.87

方案三

70.66

122.34

8349.6

86.82

2.97

                                                      

2. Used in other industrial boilers in the flue gas waste heat recovery device

Under normal circumstances, the economy is in priority in power plant application. This is because in other industrial boiler systems, the available steam resources are limited. For users with not enough steam, the recovery of heat can be considered 100% available resources, the most economical.

(1) flue gas waste heat exchanger advantages

◆ improve the efficiency of recycling, reduce coal consumption;

◆ improve the efficiency of dust removal (before the installation of dust collector);

◆ reduce the evaporation of desulfurization tower, saving water.

(2) the problems and solutions of the flue gas waste heat exchanger installed in the tail flue of the boiler

◆ low temperature corrosion solution

☆ design a reasonable choice of metal wall temperature, and the use of metal surface temperature control technology real-time control

☆ choose corrosion-resistant materials

ND steel (09CrCuSb) - at home and abroad the most ideal "resistant to sulfuric acid low temperature dew point corrosion" with steel.

ND steel corrosion rate comparison, mg / cm2.h (70 degrees Celsius 50% H2SO4 solution soak for 24 hours):      

钢种

ND                         

CRIR(日本)

1Cr18Ni9

Corten 

20G

腐蚀速率

7.30

13.40

21.70 

63.00

103.50

☆ use of low oxygen combustion

☆ Acceptable limited corrosion rate: Corrosion rate ≤ 0.2 mm / year

◆ Wear solution

◆ The main factors affecting wear:

a. Fly ash particles characteristics and concentration: SiO2 content is high, wear and aggravate

b. tube arrangement and scouring way: sequence: the first row; stagger arrangement: the second row

c. Maximum wear position: the first row of 45 ° - 60 ° (the wind on both sides of the center of the wind angle) stagger arrangement: 30 ° -45 °

d. Airflow direction: gravity effect

e. wall material and wall temperature: wall temperature increases the oxide film hardness increases

☆ choose a reasonable flue gas flow rate: not less than 6m / s

☆ using anti-wear device

1. Anti-wear tile 2. Anti-wear curtains

☆ integrated heating surface comprehensive utilization technology

H-finned tube, select a reasonable fin height and rib pitch, the flue gas flow through the finned tube will be under the action of the viscous force in the fin surface to form the surface layer, the emergence of smaller vortex In addition, under the action of fins, the flue gas scouring is not as concentrated as the light pipe in the range of 45 °, but is distributed evenly along the surface of the pipe, reducing the outer surface of the pipe Of the local wear.

◆ fouling solution:

☆ choose a reasonable flue gas flow rate (not less than 6m / s)

☆ use of soot device

☆ heat transfer surface with a reasonable layout: stagger column layout, the appropriate pitch - to enhance airflow disturbance

☆ heat exchanger elements in one go - H-type finned tube

◆ Flue gas resistance solution:

☆ the margin of the fan

☆ reasonable layout of the tube row, reduce the resistance to the acceptable range

☆ arranged before the induced draft fan

technical parameter

cases